No one can work out what colour these flip flops are

Back in February 2015, the whole word was asking itself: blue and black or white and gold?

For a couple of days, it was all about 'the dress'.

Well, just when you thought it was safe to go back on Twitter, it seems it's happening all over again - this time with a pair of flip flops.

On Thursday night, Falsiane, a Portuguese Twitter account, posted a photo taken in a shop of a pair of flip flops, along with the question (in Portuguese) 'What colour do you see?'

As we saw with the dress, the colours in the photo have been distorted. The amount of light in the background means our brains can't actually determine what colour the flip flops are - gold and white, blue and black, or even grey and blue.